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Nutrition Guidelines: Why is Serving Size Important?

Personal training clients have most nutritional success with simple, achieveable changes. Read this article to see how altering a serving size can transform an unhealthy diet into a healthy one.

The national nutrition guidelines of most countries refer to a ‘recommended numbers of servings per day’ of the major food groups, namely; fruits and vegetables, breads and cereals, dairy products and meat and meat alternatives.  But what is a serving size and why are serving sizes important?  The following table provides examples of what one serve constitutes among the various food groups;


Serving Size Example



    • 1 medium potato or similar sized root vegetable (yam/taro/carrot) (155g)
    • ½ cup cooked vegetable e.g. spinach, watercress, peas, corn (50-80g)
    • ½ cup salad or mixed vegetables (60g)
    • 1 medium sized tomato (80g)


    • 1 apple, pear, banana, orange (130g)
    • 2 small apricots or plums (100g)
    • ½ cup fresh fruit salad
    • ½ cup stewed fruit (135g)
    • 1 cup fruit juice (250ml) or 1 serving of dried fruit (only 1 serving counts)

  Breads and Cereals

    • 1 bread roll (50g)
    • 1 muffin (80g)
    • 1 medium slice bread (26g)
    • 1 cup cornflakes or similar breakfast cereal
    • ½ cup muesli (55g)
    • ½ cup cooked porridge (130g)
    • 1 cup cooked pasta (150g)
    • 1 cup cooked rice (150g)
    • 1 cup cassava or tapioca (150g)
    • 2 plain sweet biscuits (14g)

   Milk and Milk Products

    • 1 large glass milk (250ml)
    • 1 pottle yoghurt (150g)
    • 2 slices cheese (40g)
    • 2 scoops ice-cream (140g)

   Lean Meat, Chicken, Seafood, Eggs, Cooked Dried Beans, Peas, Lentils

    • 2 slices cooked meat (100g)
    • ¾ cup mince or casserole (195g)
    • 1 egg (50g)
    • 1 medium fillet of fish (100g)
    • 1 medium steak (120g)
    • ¾ cup dried cooked beans (135g)
    • 2 drumsticks or 1 chicken leg (110g)

Why is it important to understand what a serving size is?


In many cases the most effective change your personal training clients can make to improve their nutritional intake is to adjust the serving sizes of the foods they eat.  This simple, (although by no means easy change) could be all that is required to transform an unhealthy diet into a healthy diet. 


For example; you may review a client’s nutrition and lifestyle logbook to find out what they eat on a typical day.  On first impression it may look good – they may even appear to meet their national nutrition guidelines.  It’s only upon further investigation that things might start to appear a little less than ideal.


nutrition%20guidelines%20big%20steakYour clients log may show they have 1 serve of meat in the evening  (a nice juicy steak).  No problems there…or is there?


Does your client know what a serving size is or just that they had ‘a’ steak for dinner?  When you ask them about the size of the steak they tell you that it filled up most of the plate (they really love steak!), in fact it turned out to be a 400gram whopper!  Now in reality the client has had more than three serves of meat in this one meal, and being that its meat with a lot of fat running through it they would have consumed a mass of calories through the fat that was in the steak.


So with this client there’s actually no need for them to make radical changes to their diet, rather they just need help to alter the size of their serving to bring them more in line with what a recommended serving size actually is, and fill themselves up with a lower calorie alternative that is palatable to them such as more of their preferred vegetables.


If you know your national nutrition guidelines (every personal trainer should…) then you’ll know that wholegrain bread and cereal products, and fruits and vegetables should make up the majority of a persons diet. 


Using a visual representation, such as this plate, can help many clients to understand how the guidelines for the intake of these foods and their recommended serving sizes translate into the makeup of their dinner plate. 


As the over consumption of food (or calories specifically) is a major issue in the western world its vital that personal trainers investigate where extra calories are being consumed by clients.  Often it’s in larger than normal serving sizes of high calorie foods, specifically foods with a high fat or alcohol content.


Remember that fat has more than twice the amount of calories as an equivalent quantity of carbohydrate or protein.  And while not as high as fat, alcohol has almost twice the caloric content of an equivalent quantity of carbohydrate and protein.


personal%252520training%252520big%252520wineSo as a personal trainer get into the habit of investigating the serving sizes of your client’s alcoholic drinks as well as the foods that may contain a large number of calories – it may unlock the secrets to success for you and them. 


And when you’re out celebrating your next personal training achievement don’t be too disappointed when the bartender pours you a ‘standard drink’,  it may well be much better on your waistline, albeit harder on your pocket and current value system!

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